US President Donald Trump makes his way to board Marine One before departing from the South Lawn of the White House on February 1, 2018 in Washington, DC. (Photo by AFP)

Senior US officials have claimed President Donald Trump is prepared to launch military action if necessary against the Syrian government which they say is possibly developing new types of chemical weapons.

The officials on Thursday said the government of Syrian President Bashar al-Assad saved a part of chemical weapons stockpile despite a US-Russian deal under which Damascus had agreed to hand over all such weapons for destruction.

The government surrendered its stockpiles of chemical weapons in 2014 to a joint mission led by the UN and the Organization for the Prohibition of Chemical Weapons (OPCW), which oversaw the destruction of the weaponry. The deal was negotiated by Russia and the United States.

The officials, speaking on condition of anonymity, told reporters in Washington, DC, that Syrian armed forces “evolved” their chemical weapons and made continued occasional use of them in smaller amounts since April 2017. But they declined to provide specific details.

More than 80 people died in the April 4, 2017 sarin gas attack on Khan Shaykhun in Idlib Province. Following the incident, the US military launched a missile strike on a Syrian air base.

The United States and the militants operating in the area blamed the Syrian government for the deadly incident. Syria and Russia, however, rejected the claims, suggesting that a militant weapon may have detonated on the ground.

US Navy guided-missile destroyer USS Porter (DDG 78) conducts strike operations while in the Mediterranean Sea which US Defense Department said was a part of cruise missile strike against Syria on April 7, 2017. (Photo by Reuters)

“We reserve the right to use military force to prevent or deter the use of chemical weapons,” one official said.

A second official said if the international community does not act quickly to rein in Syria’s chemical weapons, they could spread beyond its borders and possibly even “to US shores.”

“It will spread if we don’t do something,” the official warned.

In June last year, the fact-finding team from the OPCW published the results of its probe of the April 4 incident, confirming that the chemical substance in the Khan Shaykhun incident had been the nerve gas sarin.

In response, Moscow described the OPCW report as “very biased,” arguing that the report failed to address the question of who was responsible for the gas incident and how the chemical had been used.

Last week, Secretary of State Rex Tillerson said Russia bears some responsibility for failing to enforce the chemical weapons ban on Syria, and claimed that the Syrian government used chemical weapons against militants in recent operations.

Russia has denied any complicity, and the Syrian government has said it has not carried out any of the attacks, saying such accusations are merely meant to hinder efforts to find a peaceful solution to the conflict in the Arab state.